Hydraulic valve lifter



Feb. 9, 1954 G, T RANDQL 2,668,524

HYDRAULIC VALVE LIFTER Filed May 4, 1951.

[ffl A I INVENTOR; I l||| q Glenn T. Randol,

Patented Feb. 9, 1954 UNITED STATES PATENT OFFICE HYDRAULIC VALVE LIFTER Glenn T. Randol, Mountain Lake Park, Md. Application May 4,*1951, Serial No. 224,485

15 Claims.

The present invention relates to self-adjusting valve lifters adapted to maintain substantially zero clearance in the valve drive train of an internal-combustion engine. The invention particularly relates to improvements in hydraulic valve lifters. Y

'Valve lifters of the mechanical type presently used commercially do not provide for automatic adjustment of the valve drive train, nor for automatic elimination of backlash in the valve operating mechanism of an internal-combustion engine. In mechanical drive trains, clearance is provided between the rocker arms of the drive train and the stems of the valves. As the engine is operated, the clearance is increased due to the impact and wear to which the train is subjected. Increased clearance between the rocker arms and valve stems results in ineiiicient and noisy operation of the engine and requires a partial disassembly of the engine to adjust the tappets; that is, to temporarily correct the clearance between the rocker arms and valve stems by veifecting a manual adjustment in the drive train.

To avoid the necessity of frequent tappet adjustment and to eliminate noisy and ineicient operation of the engine, some commercial engines are equipped with hydraulic valve lifters which attempt to effect automatic adjustment of the valve drive train to maintain zero clearance in the train, so that in effect, the train functions as a solid body in opening the valves in the engine.

The object of the present invention is to pro-- vide an improved hydraulic valve lifter mechanism capable of constantly and consistently maintaining zero clearance and effectively eliminating backlash in the valve drive train of an internal-combustion engine.

Another object of the invention is toV provide a hydraulic valve lifter particularly adapted for use with a conventional valve operating cam, which lifter is of optimum design forV maintainingsilence of operation and aifording long life for the cam itself and the mechanism operated. thereby.

Briey stated, I provide, according to the present invention, an improved hydraulic valve lifter mechanism comprising a pair of relatively movable body members adapted to be disposed between a valve operating cam and an Vengine valve with one member in engagement with the cam and the other in operative engagementwith the valve stem, at least-one of the members hav-I ing uid passageway means and a port .therein leading to a uid pressure chamber dened be- 2 tween the two members, and a check valve in the iluid pressure chamber for controlling flow through the said iiuid passageway means.

One object of the present invention is toY provide, in the mechanism briefly described, means for positively actuating the valve, rather than to rely upon a hydraulic impact principle or the like as has been conventional heretofore.

It is also an object of the present invention to provided, in one embodiment, a hydraulic valve lifter utilizing a separate, engine cam actuated,` cam member to eifect closing of the port leading to the uid pressure chamber in the valve lifter mechanism prior to actuation of one member of the mechanism by the engine cam to maintain zero clearance in the valve drive train of the internal-combustion engine, in which the valve lifter is embodied.

Another object of the present invention is to provide a hydraulic valve lifter utilizing a resilient sleeve in the actuating means for the check valve of the mechanism. The resilient sleeve is particularly advantageous in facilitating uniform movement of the check valve upon each actuation thereof, re` gardless of the relative. disposition between'the two body members of the lifter mechanism to establish Azero-lash condition. In this vconnection, it is an object of the present invention toi provide Va hydraulic lifter mechanism utilizing a resilient sleeve mounted on one of the members of the mechanism and'adapted to frictionally engage the other member ofthe mechanism in such manner as to Ycooperate with other elements in a valve lifter mechanism for eifecting uniform actuation and movement of a check valve upon each actuation of the valve lifter mechanism.

It is a further object of the invention to provide a hydraulic valve lifter utilizing the resilient sleeve or ring referred to hereinbefore in conpresently used commercially,v whether mechanical or hydraulic.

An additional object of the to provide an improved valve lifter mechanismthat disposition of the body members and eifective to compensate for any relapresent invention isV tive movement between the body members of the valve lifter mechanism.

Another object of the invention is to provide a valve lifter mechanism which includes means for accommodating relative movement between the members of the mechanism to compensate for any backlash in the valve drive train and to establish zero clearance therein upon closing of the engine valve.

A further object of the invention is to provide separate means for effecting closing of a check valve in a main fluid pressure chamber of the lifter mechanism prior to actuation of the lifter mechanism for opening the engine valve,- se that zero clearance is consistently maintained in the valve drive train.

In accomplishing the objects of the present invention, I provide a valve lifter mechanism including, as has been briefly referred to hereinbefore, a pair of relatively movable body members defining a fluid pressure chamber therebetween. Passage means, including a port in one body member, are provided for conducting fluid under pressure to the chamber. A check valve is positioned within the chamber and is adapted to be moved to close the port in the one body member and thus to close the pressure chamber. The fluid in the chamber is substantially incompressible and as a result the fluid prevents relative movement between the body members in one direction when the check valve is closed. rlhe body members are, in effect, locked together for conjoint movement to open the engine valve. Rather than rely on the unsatisfactory hydraulic impact principle utilized in commercial hydraulic valve lifters to move the check valve to closed position, I provide mechanical means for forcibly and positively moving the check valve to its seated condition. In one embodiment of the invention, the

mechanical means includes a stem extending through one of the body members for engagement with a special cam surface on the engine cam for closing the check valve immediately prior to actuation of the body members by the engine cam. In this embodiment, all clearance in the valve drive train is eliminated. In a second embodiment of the invention, the valve is moved to its seat mechanically during an initial portion of the movement of the body members of the lifter, so that a slight amount of fluid in the pressure chamber may escape resulting in a slight amount of clearance for backlash, but not to a degree as would be objectionable.

As a substitute for, or as a supplement to, the mechanical means referred to, I provide a sepi arate hydraulic dashpot for moving the check Valve to its seat. Actuation of the check valve by means of the dashpot does not require impact actuation and is substantially positive in action. The dashpot may be included in either embodiment of the invention.

Both the mechanical means and the hydraulic dashpot for effecting closing of the check valve involve a pair of relatively movable members, one an actuating member and the other an actuated member carrying the valve. The actuated member or valve member is movable between defined limits and the actuating member is movable with respect thereto to accommodate and compensate for relative movement between the body members in taking up clearance in the valve drive train. The dashpot and/or the mechanical means are capable of accommodating relative movement between the actuating and actuated members and yet provide a positive driving con- 4 nection between the members to move the valve member from one defined limit to the other defined limit of movement.

In addition to the foregoing, other objects and advantages of the present invention will become apparent in the following detailed description of preferred embodiments of the invention, wherein reference is made to the accompanying drawings, in which: i

Figure 1 is a fragmentary vertical sectional View through an internal-combustion engine, showing in elevation the valve lifter mechanism constructed in accordance with the principles of the present invention;

Figure 2 is an enlarged vertical sectional view taken substantially along the line II--II of Fig ure l, looking in the direction indicated by the arrows, and showing my valve lifter mechanism in engine valve closed position;

Figure 3 is a detailed vertical sectional view of the valve lifter mechanism of Figures l and 2 with the parts thereof in locked-up zero clearance condition just prior to opening of the engine valve;

Figure 4 is a transverse sectional view taken substantially along the line IV--IV of Figure 3, looking in the direction indicated by the arrows;

Figure 5 is a transverse sectional view taken substantially along the line V-V of Figure 3, looking in the direction indicated by the arrows;

Figure 6 is a partial vertical sectional view of a modied embodiment of the present invention, showing only the part of the valve lifter mechanism wherein modification has been made; and

Figure 7 is a transverse sectional view taken substantially along the line VII-VII of Figure 6, looking in the direction indicated by the arrows.

Referring now to the drawings, and particularly to Figures 1 and 2, I have shown a preferred embodiment of my invention incorporated with a conventional internal-combustion engine I0 having a plurality of valves, one of which is shown at l l in Figure 2. A valve drive train indicated generally at l2 is provided, as is well understood, for each valve of the engine, and the valve drive train is conventional in all respects except for the valve lifter mechanism I3 of the present invention, which is embodied therein. The valve drive train l2, as shown, extends between the valve Il and the cam shaft I4 of the engine. The valve l l may be of any known construction and the valve selected for illustration includes a stem portion I6, guided in a collar part l1, and having spring means I8 associated therewith for normally tending to close the valve. A rocker arm i9, pivotally mounted intermediate its ends on an oil distributing pipe 28, is adapted to bear at one end 2l thereof against the free end of stem it when rotated in a clockwise direction as viewed in Figure 2 of the drawings, to open valve Il against the force of the spring means I8. The other end 22 of the rocker arm I9 has a tting 23 secured therein, and with which is asso. ciated a connector member 24 having one end of a hollow push rod 25 secured thereto. Referring again to Figure 2, the other end of push rod 25 has a connector 26 secured thereto, which bears against the dished upper end portion of an inner body member, indicated generally at 2l, which is mounted, in the embodiment of the present invention herein disclosed, for vertical sliding movement in a bore 28 of an outer body part 29. The inner body part 2T and the outer body part 29, as will presently appear, form a part of the lifter mechanism i3 of the present invention,

The end portion 22 of the rocker arm I9,v 'fitting 23, connector 24 and member 26 are provided with suitable bores, and, together with the hollow rod 25, conduct oil under pressure from the pipe of the pressure lubricating system of the engine to a bore 30, formed centrally of the inner body part 21, and thence to a chamber or reservoir 3l provided in the inner body member 21, to a bore 32 at the lower end of the inner body member 21, and thence to a chamber, indicated generally at 33, defined between the lower end of the inner body member 21 and the lower end ofk the bore 28 or inner end wall of the outer body member 29. The function and purpose of the chamber 33 will be referred to in greater detail hereinafter.

The lifter mechanism I3 of the present invention comprises the outer body part 29, the inner body part 21 mounted for rectilinear sliding movement and free rotational movement in the bore 28 of the outer body member 29, spring means 34 confined between the inner body member 21 and the outer body member 29 tending to separate but accommodating relative movement in either direction between the two, a cage 35 for receiving a ball check valve 36, a ball supporting stem or inner stem member 31, a hollow actuating plunger or outerstem member 38 withinV which the stem 31 is received, spring means 39 between the inner body member 21 and the ball supporting stem 31 and spring means 4l) between the cage 35 and the actuating stem 38. The outer body member 29, adjacent the upper end thereof, is formed with an annular groove 4I for receiving a snap ring 42 which serves to retain the inner and outer body members in assembled relation when the valve lifter mechanism I3 is removed from the block of the engine.

The inner body member 21 comprises a bod member 43 having an enlarged axial bore forming the reservoir 3| and terminating at its lower end in a valve seat 44. formed by a conical counterbore in the bore 32. The body member 43 is closed at its upper end by a plug 45, which is preferably threaded into the open end of the body member 43. The threaded connection between the plug 45 and the body member 43 has been indicated as being preferable, but it is apparent that the plug 45 could be press-fitted into the body member 43, or the body member and the plug could be united in any usual manner to provide the reservoir 3 I. The plug 45 is dished at its upper end to receive the connector 26 and is provided with the bore 30 establishing communication between the hollow push rod 25 and the reservoir 3I.

The cage 35 is generally cylindrical and is provided at its upper end with a radial flange 46 resting against the lower surface of the body member 43. The valve seat 44 is preferably formed in or at the end of a reduced extension of the body member 43 that fits within the cylindrical portion of the cage 35. The cage 35 is provided at its lower end with a reduced cylindrical portion 41 intimately, but slidably, engaging the exterior surface of the ball supporting stem 31. The ball supporting inner stem 31, which is also referred to herein as a pedestal and an actuated member, is provided at its upper end with a flange 48 arranged to normally rest upon a radial flange 49 provided between the cylindrical portions of the cage 35. The upper end of the pedestal 31 is provided with a dished portion 58 within which the ball 36 is cradled. It is apparent that the pedestal and ball can readily be combined to Vform a unitary valve memben-i structure. The ball 36 is confined between the inner stem 31, the valve seat 44 vand the cage 35. The inner stem 31 is slidably and rotatably mounted within the hollow outer stem 38, which is also referred to herein as an actuating mem-f ber, and is provided with a circumferential groove 5I within which an expansible and contractible resilient split-sleeve or ring 52 is fitted. The ring 52 frictionally engages the inner walls of the hollow stem 38 and is adapted to bind the stem members 31 and 38 together for conjoint movement, but is capable of accommodating relative movement between the two stem members. The spring means 39 is preferably relatively light and is compressed between the valve seat 44 and the flange 48 of the inner stem 31.l

The spring means 40 is also light and is confined between the flange 49 on the cage 35 and a'ilange 53 at the top of the outer stem 38. The flange 53 on the stem 38 is preferably'turned up to provide a cup within which the lower end of the spring means 40 is received.

The outer stem 38 is slidably mounted in a bore 54 in the end portion or wall of the -outer body member 29 and extends toV the exterior thereof to engage the surface of the cam I 4. The cam I 4 provided with a conventional cam surface and is also provided, in its base circle portion, with a groove 55 for the reception of the lower end of the outer stem or actuating plunger 38. Since the stem 38 is preferably slidably and rotatably mounted in the bore 54, the bore and the surface of the stem 38 are preferably lapped to provide a metal to metal seal. However, a resilient sealing ring, such as a neoprene O-ring, may be utilized in a customary manner.

Referring again to the various bores and passageways establishing communication between the engine lubricating system and the chamber 33, it will be seen that the inner stem 31 is provided with a plurality of inclined or angular bores 56 establishing ycommunication between the upper surface of the stem 31 and an axial bore 51 in the stem. The axial bore 51 communicates with a dashpot or hydraulic chamber 58 between the stem members 31 and 38. A plurality of radial bores or passages 59 are provided in the cylindrical wall of the cage 35 to establish communication between the chamber 33 and the reservoir 3i in the inner body member 21. When the ball 36 is not seated against the valve seat 44, it is apparent that hydraulic iiuid from the pressure lubricating system of the engine will be forced into the chamber 33 and the lchamber 58. Continuous circulation of lubricant through the lifter mechanism is provided for by a small radial passage 68 in the body member 43 of the inner body member 21, which bore orv passage communicates with the reservoir 3| in the inner body member 21. Since the bore 68 is small in size, it forms a restricted passage for the flow of lubricant, which allows a slight continuous flow, but

not such flow as will relieve the lubricant pres` sure in the chambers 3l, 33 and 58.- The radial passage 60 communicates at its outer end with a shallow circumferential groove 6I in the body member 43. A bore 62 in the outer body member 29 establishes communication between the circumferential groove 6I and a circumferential groove 63 in the outer surface of the outer body member 29. The outer bodymember 29 has a relatively intimate engagement within the bore provided in theV cylinder block, Vbut suicient clearance exists between the outer body member 29 and said bore to accommodate leakage of oil from the circumferential groove 33 to the lubri cant reservoir or sump of the engine.

The manufacture and assembly of the valve lifter mechanism or" the present invention `are readily and economically `accomplished. In assembl the spring 34 is positioned in the bore 28 of the outer body member 29 and the outer stem member 38 is slid into the bore E4 in the end Wall of the outer body member 29 with the ilange v53 preventing passage of the stem 38 entirely through the bore 54. The spring means 40 is then positioned on top of the stem 3S and the cage 35 is positioned on top of the springs 34 and 4i), with the lower cylindrical portion 41 of the vcage being received within the confines of the helical spring forming the spring means 40. The innerzstem 31 is then slid through the cylindrical portion 41 of the cage 35 and into the hollow plunger 3S. Then the spring 33 and ball 36 are positioned on top of the inner stem 31 and the inner body member 21 is positioned on top of the spring 39 and the cage 35. The plug 45 may then be inserted into the inner body member 43, `or the assembly of the plug 45 and body 43 may -have been accomplished prior to insertion into the bore 28 of the outer `body member 23. Thereafter, the snap ring 62 is inserted in the groove 4l in the bore 28 of the outer body member .29 to -prevent accidental disassociation of the various members of the assembly,

The operation of the valve lifter mechanism I3 of the present invention is as follows:

With the engine valve in closed position, the various elements of the mechanism will assume the relative positions shown in Figure 2, in which the spring 34 between the inner body member 2.? and the outer body member 29 biases the flat bottom end of the outer body member 23 into engagement with the base circle portion of the cam i4 and normally biases the inner and outer body members away from each other but is capable of yaccommodating relative movement in either direction between the body members to establish and maintain Zero clearance in the valve drive train I2. The spring 39 is of suicient strength to maintain the flange 43 on the inner stem or pedestal 51 in engagement with the flange r 49 of the cage 35. The spring 43 is of sunicient strength to bias the outer stem or actuating member 3B into engagement with the groove 55 in the base circle portion of the cam I4.

As the cam rotates in acounterclockwise direction, as indicated by the arrow, to the position shown in Figure .3, the actuating member 33 is acted upon by the terminus of the groove in the cam I4 and is moved upwardly. Due to the frictional engagement of the split-.sleeve or ring 52 with the interior surface of the stem 38 and the engagement thereof in the circumferential groove 5.1 `in the inner stem 31, the inner stem .3 1 is moved Aby the outer stem 38 to force the ball 39 into engagement with the valve seat 44 to close the valve port 32. At this point, the outer body member 29 has not yet been acted upon by the cam I4 and accordingly, it is apparent that all or 4the luid in the chamber 33 is trapped therein prior to actuation o the outer body member 29. Continued movement of the cam I4 in a counterclockwise direction forces the outer body member 29 upward and since the duid in chamber -33 is substantially incompressible, the outer and inner body members will .be moved conjointlyto effect S actuation of the valve drive train :l2 to open the engine valve II.

0n further rotation of the .cam I4 in a counterclockwise direction from the lposition shown in dotted lines in Figure 3 to the position shown in Figure 2, force on the outer body member 29 will be relaxed and the spring 34 and fluid in the chamber 33 will bias the outer body member into engagement with the cam I4. The spring 34 and the `fluid in the chamber 33 will tend .to separate the body members to take up any clearance in the valve drive train, but will, if required, accommodate relative movement of .the body members toward one another to effectively shorten the valve drive train, thereby serving to correctly establish and maintain zero clearance in the valve drive train. At the same time, the spring 39 and spring 49 cooperate .to move the stem members 31 and 38 downwardly with respect to the outer body member 29 to accommodate movement of the ball off the seat 44 to open the port 32 for free passage of huid from the reservoir 3i to the chamber 33, or vice versa Aas is required, according to adjustment made in the valve drive train. Spring further acts to bias the outer stem 38 into engagement with the groove in the cam I4, the operative connection between the two stems accommodating relative movement therebetween as required according to the adjusted relative positions kof the body members. The valve lifter mechanism .is nowin position to repeat the opening cycle just described.

The valve seat 44 cooperating with the ball 3 6 forms a limit stop vfor movement of the valve member in .one direction and 'the ange 49 on the cage 35 cooperating with the flange 48 forms a limit stop for movement of the valve member in the opposite direction. It is therefore apparent, that .the actuation o the member 31 and thus of the ball 33 must be identical upon each actuation of the valve lifter mechanism. The provision of limited and deiinitely defined movement of .the 'ball check valve is of particular advantage since the clearance of the valve in the open position may be set and established for 4an ultimate operating condition and yet only a limited amount of movement need -be imparted to .the valveto close the pressure chamber 33 Aupon each actuation of the valve lifter, which limited and dei-ined movement can readily be accomplished before the outer body member -29 is acted upon by the cam I4. Due to the fact that the body members 21 and 29 are capable of relative movement, means must be yprovided for allowing relative movement between the cam I4 and the valve so that the valve will be positively actuated by the cam i4 and at the same time will have only the limited uniform movement described. To accommodate such relative movement and to simultaneously insure the uniform actuation of the valve 36 upon each actuation of the lifter mechanism, the split ring 52 is provided between the inner stem'31 and the outer stem 38. When it is necessary for relative movement to occur between the outer stem 33 and the inner stem 31, the resilient ring 52 is capable of contracting radially, or being compressed radially, to accommodate the relative movement lbetween the two stems. Yet, the resilient ring 52 exerts sun-leicht frictional engagement with the inner wall of the stem 38 to insure substantially positive actuation of the valve 36 upon .each actuation of the lifter mechanism by the-cam 14. The resilient ring .or sleeve 52 is, therefore, an important Vfeature .of

the present invention since it accommodates and facilitates provision of the uniformly actuated valve for closing the pressure chamber 33.

In actual operation, the design of the apparatus is such that the actuating member 38 will normally be required to move a distance in excess of the movement required to close the valve 36. When sufficient movement has occurred to effect moving of the ball 36 onto the seat 44, the resilient sleeve or ring 52 will contract to accommodate slight relative movement between the stems 31 and 38 and such additional movement insures effective seating of the valve against the seat. The movement imparted to the actuating member 38 by the cam I4 can be varied to a considerable extent and accordingly, such surplus or extra movement of the outer stem is readiiyaccomplished prior to actuation or movement of the outer body member 29 by the cam I4. It is therefore apparent that the actuation of the check Valve 36 will always be uniform regardless of the relative disposition of the body members 21 and 2S.

The relative movement between the body mem-4 bers 21 and 2S and between the stems 31 and 33 is effected by means of the springs 34 and 4i), respectively, while the lower surface of the outer body member 29 is engaged with the trailing edge of the eccentric portion of the cam I4 so that the parts and elements of the mechanism will again return to the position shown in Figure 2, wherein the cam has rotated to the extent necessary to bring the base circle portion thereof into engagement with the under surface of the outer body member 29 and the groove 55 thereof into engagement with the under surface of the outer stem 33. During operation of the mechanism, all of the members are free to rotate with respect to one another so that a rotary cleaning movement exists to clear the mechanism of any dirt or sediment that may accumulate or be present in the lubricating oil of the engine. Clogging due to sediment in the oil or hydraulic iiuid has been a serious disadvantage of hydraulic valve lifters presently used commercially.

It will be observed that in the operation of the valve lifter mechanism of the present invention, the chamber 58 between the inner stem 31 and the outer stem 38 is constantly filled with lubricant due to its connection with the pressure lubrication system of the engine, as previously described. The oil thus delivered to the chamv ber 58 will act to retard relative movement between the inner stem 31 and the outer stem 38 in effecting engagement of the check valve 36 with the seat 14. yIhus, the pressure of the oil in the chamber 58 supplements the action of the resilient sleeve or ring 52 to control or maintain uniform actuation of the ball check valve irrespective of the adjusted condition of the body members 21 and 29. The oil pressure chamber S thus provides a dashpot effect Which initially resists a slight relative movement of the inner and outer stems, with respect to each other, and later is also effective to assist the spring 40 in effecting any necessary relative movement between the two stems.

The dashpot effect of the chamber 58, as described, may be varied so as to be partially ef.

fective to supplement the action of the sleeve or ring 52, may be completely inoperative. so that the resilient sleeve or ring acts entirely independently, or may be completely operative so that the resilient sleeve 52 may be omitted.

Where desired. The dashpot effect of the chamllin 10 ber 58 is rendered completely inoperative by providing bores 56 and 51 in the inner stem 31 of relatively large diameter and the dashpot effect may be rendered operative to the exclusion of the resilient sleeve or ring 52 by providing bores 56 and 51 in the inner stem 31 of restricted cross section. In the latter case, the configuration of the groove 55 and the cam I4 may be varied to provide impact for eiecting actuation of the outer stem 38 whereby the check valve 35 is moved to its seat solely by the dashpot action of the hydraulic fluid in the chamber 58. If the dash-` pot is to be used to supplement the action of the resilient sleeve or ring 52, the diameter'of the bores 56 and 51 is selected to provide partially restrictive passage of iiuid.

As the valve lifter mechanism is operated and the check valve is moved onto its seat, very little, if any, uid will be forced out of the chamber 33, since the fluid will readily pass around or bypass the ball. As a result, the chamber 33 will remain entirely filled with fluid and there will be no relative movement between the body members 21 and 29 when the body member 29 is moved by the cam I4.

It is apparent then that true and complete zero-lash adjustment is made while the mechanism rides the base circle of the cam IllV and that said adjustment is constantly and con-- tinuously maintained. Such zero-lash adjustment cannot be maintained in present commercial lifters, since check valve actuation is reliant upon impact actuation of the outer body member, and movement of the outer body member forces fluid out of the pressure chamber before the check valve can be seated.

valve seats properly, which further renders operation of commercial lifters impractical.

From the foregoing description, it will appear that in one embodiment of the present invention, I provide separate means actuated by the engine cam to uniformly actuate the check valve through a predetermined degree of movement regardless of the relative axial relation established between the inner and outer body members.

insuring complete closing of the iiuid pressurer chamber prior to actuation of the outer body.l member, the present invention can be effectively practiced Without resorting to separate means such as the stem 33 separately actuated by the cam of the engine. In Figures 6 and 7, I have shown a, further embodiment of the present invention which will fall somewhat short of the advantages and eiectiveness of the embodiment,

o-f the invention previously described, but is a commercially effective mechanism. While the embodiment of the invention as disclosed in Figures 1 to 5 inclusive, eliminates all clearance and vbacklash, the embodiment of the invention shown in Figures 6 and 7 Will allow a very minute amount of clearance at the instant of valve opening. This amount of clearance, however, is not disadvantageous to the operation of the vehicle engine, and is much less than that occurring in present commercial hydraulic and mechanical valve lifters.

Referring now to Figures 6 and 7, parts or elements similar or identical to parts or elements of the previously described embodiment of the In addi` tion, the seating of the check valve is not pos-v itive and leakage frequently occurs before theinvention have been indicated by the same reference numeral with the suffix a. In this embodiment of the invention, the outer stem for direct actuation by the engine cam has been omitted and an outer hollow stem or actuating member 38a is provided by a cylindrical portion formed integrally with the bottom or end wall of the outer body member 29a. The inner stem or pedestal 31a is mounted for sliding movement within the cylindrical portion dening the stem 38a and a resilient split ring or sleeve 52a frictionally engages the side walls of the inner surface of the cylindrical portion so that said portion is eiective to actuate the check valve 38a. In operation, the cam Het is of conventional design and is not provided with the special groove 55 and accordingly, as the cam lila rotates from the position shown in Figure 6, which is the same as the position shown in Figure 2, to a position the Same as that shown in Figure 3, the lower surface of the outer body member 29a merely rides upon the base circle of the cam Ma. As the cam Mc continues rotating in a counterclockwise direction from the position corresponding to that shown in solid lines in Figure 3, to that shown in dotted lines in Figure 3, the outer body member 29a is acted upon and is moved upwardly.

Immediately upon initial upward movement of the outer body member 29a, the cylindrical portion 38a is eifective to move the inner stem 31a upwardly, due to the frictional engagement of the ring 52a with the inner surface of the cylindrical portion 38a, to move the check valve 36a to its seat 44a. The amount of relative movement between the outer body member 29a and the inner body member 21a to eiect seating of the check valve 35a is very slight and as a result only a slight amount of lost motion occurs, so that the valve drive train has very little clearance therein. After the check valve 3Go has been moved to its seat 44a, the body members 21a and 2Scrr are moved conjointly by the cam lila, due to the incompressibilty of the fluid trapped within the chamber 33a. When the eccentric of the cam Mc pases over center, the spring 34a and the fluid in the chamber 33a, will normally tend to bias the body members 21a and 25a away from one another, as previously described with regard to the embodiment of Figures l to inclusive, to take up any backlash existing in the valve drive train. If required, however, the spring 34a and the fluid in the chamber will accommodate movement of the body members toward one another to provide zero clearance in the valve drive train without over-adjusting same. At the same time, the spring 35a moves the inner stem 31a downwardly to open the check valve 36a, and allows free flow of fluid through the port 32a. The spring 39o, is effective to move the inner stem 31a against the limit stop defined by the flange 45a on the cage 35a Further relative movement between the body members 21a and Zea will effect relative sliding movement between the cylindrical portion 33a and the inner stem 31a, the resilient ring or sleeve 52a being compressed radially inward to accommodate the relative movement.

The passage 56a and 51a establish communication between the pressure chamber 33a and the dashpot chamber 58a located between the outer body member 29a and the inner end of the inner stem 31a, The dashpot 58a is adapted to serve the same purpose as the dashpot described with regard to the embodiment of the invention' disclosed in Figures 1 to 5 inclusive.

As previously pointed out, the particular construction provides for uniform actuation o the check valve 36a upon each adjusted actuation of the valve lifter mechanism. Due to this uniform actuation, the check valve 35a may be positioned close to its seat Ma so that only minute movement of the stem 31a need be effected to close the pressure chamber 33a. Accordingly, the amount of relative movement between the body members 21a and 29a is very slight before the pressure chamber 33a is closed and, therefore, the momentary loss of zero-lash adjustment will be very slight and will result in a very minute increment of clearance in the valve drive train. Furthermore, the ability of the check valve to quickly restore itself to full open position allows for the rapid take-up of backlash or relief of over-adjustment in the valve drive train, as required. The amount of clearance and backlash in presently used comercial valve lifters is much greater than the small, unobjectionable amount of clearance occurring in the valve lifter of the present invention.

In both embodiments of the invention, I have provided hydraulic valve lifter mechanisms having the normal advantages of silent and efficient operation, and in addition, having the advantages of maintaining substantially zero clearance in the valve drive train and substantially eliminating backlash therein. In both embodiments of the invention, I provide means for positively effecting seating of the check valve for the fluid pressure chamber prior to or at the instant of actuation of the body members of the valve lifter mechanism.

From the foregoing description, it will appear that the split-sleeve or resilient ring is adapted to uniformly actuate or move the check valve through a predetermined stroke regardless of the relative axial relation established, between the inner and outer body members. Were it not for the provision of the split-sleeve, the check valve would not actuate uniformly into and out of engagement with its seat. If this feature were not incorporated in the invention, the greater the separation of the inner and outer body members, the greater the stroke required of the valve. As the separation of the inner and outer body members increases, the necessary stroke of the valve would correspondingly increase to an undesirable and impractical degree. As will also be noted from the foregoing description, the present invention provides an infinite zero-lash adjustment, particularly the embodiment of the invention as shown in Figures 1 to 5 inclusive. While the embodiment of the invention shown in Figures 6 and '7 does not actually provide a perfect innnite adjustment, the step-by-step zero-lash adjustment of that embodiment is effective in steps defined by the movement of the outer body member necessary to bring the check valve to its seat. As a practical basis of adjustment, this movement 0r step may be less than .002 inch.

In both embodiments of the invention, opening of the check valve after actuation of the valve lifter mechanism is abetted by the pressure differential existing across the valve and accordingly, any backlash existing in the valve drive train will be immediately taken up.

According to the present invention, the check valve for the fluid pressure chamber is not closed by impact, but is closed by a substantially positive mechanical or hydraulic action. Accordingly, vthe engine cam is preferably provided with leading ramps to the center point of the cam ec.- centric, so that the valve lifter mechanismA is smoothly operated and is not subjected to the impact and shock necessary for successful operation of commercially proposed hydraulic valve lifters. The present invention is particularly adapted to be utilized in the replacement of all valve lifter mechanisms, whether mechanical or hydraulic. The embodiment of the invention shown in Figures 6 and 7 is particularly adapted for use as a replacement unit, since the valve operating cam need not be provided with a special groove in its base circle portion. While it is preferred that the cam design be conventional, as shown in the drawings, it is clear that the present invention will operate satisfactorily with the particular cam design presently used for commercial hydraulic valve lifter-s. While the life of the apparatus undoubtedly will be decreased when utilized with impact type cams, the mechanism will operate just as eiectively to maintain zerolash adjustment and to eliminate backlash in the valve drive train. I

In installing the valve lifter mechanism of the present invention in the valve drive train of an engine, it makes no difference whether the engine be hot or cold during installation since overadjustment, which would normally occur if the engine were hot during installation, and underadjustment, which would nor-mally occur if thev engine were cold during installation, are readily compensated for and eliminated by the automatic operation of the valve lifter of the present invention. y

1 It will be clear that various changes, modications and rearrangements can be made in the particular apparatus described herein without departing from the scope of my invention. For example, a diaphragm may be utilized as a check valve rather than a ball, one body member need not be mounted within another body member, the various parts and elements of the construction may be re-designed to lit particular installations or designs, and so on. Therefore, the'embodiments of my invention, shown and described, are to be considered as capable of modiiication and rearrangementY within the spirit and scope of the invention, as dened by the appended claims.

I claim as my invention:

l. A hydraulic valve lifter comprising a pair of relatively movable members defining a chamber therebetween, a source of fluid, a normally open valve port in one of said members establishing communication between said source of fluid and said chamber, a check valve movable to close said port, and mechanical means associated with said valve for moving said valve to close said ort.

p 2. A hydraulic valve lifter comprising a pair of relatively movable members defining a chamber therebetween, a source of fluid, a valve port in one of said members establishing communication between said source of uid and said chamber, a check valve arranged to be normally spaced from said port and movable toward said port to close the same, a movable member supporting said valve, and means for moving said movable member and said valve to close said port, whereby said chamber is closed to form a fluid pressure chamber adapted to prevent relative movement between said members in one direction of relative movement therebetween.

3. A hydraulic valve lifter comprlsing a pan' of relatively movable members defining achamber therebetween, a source of `iluid, a normally open valve port in one of said members establishing communication between said source of fluid and said chamber, a valve member movable to close said port, and means frictionally engaging said valve member for moving said valve member to close said port, whereby said chamber is closed to prevent relative movement between said pair of members in one direction.

4. A hydraulic valve lifter comprising a pair of relatively movable members defining a chamber therebetween, a source of fluid, a normally open valve port in one of said members establishing communication between said source of fluid and said chamber, a valve member movable to close said port, a hollow stem, a pedestal supporting said valve member slidably mounted in said stem', means on said pedestal frictionally engaging said stem, and means for moving said stem to move said pedestal and said valve to close said port, whereby said chamber is closed to prevent relative movement between said pair of members in one direction. i

5. A hydraulic valve lifter comprising a pair of relatively movable members defining a chamber therebetween, a source of fluid, a normally open valve port in one of said member establishing communication between said source of fluid and said chamber,v the iiuid in said chamber normally biasing said members away from one another and accommodating movement of said members toward one another, a valve member movable to close said port, an actuating member movable with respect to said valve member, means for coupling said actuating member and said valve member for conjoint movement, and means for moving said actuating member to move said valve member vto close said port, whereby said chamber is closed to prevent relative movement between said pair of members in one direction.

6. A hydraulic valve lifter comprising a pairA of relatively movable members dening a chamber therebetween, a source of fluid, a normally open valve port in one of said members establishing communication between said source of fluid and said chamber, a valve member movable to close said port, an actuating member movable with respect to said valve member, said actuating member and said valve member defining a dashpot chamber therebetween, one of said members having. bores therein establishing communication between said first-named chamber and said dashpot chamber, and means for moving said actuating member, the fluid in said dashpot chamber serving to couple said actuating member and said valve member for conjoint movement to close saidv port.

7. A Vhydraulic valve lifter comprising a pair of relatively movable members defining a cham-v ber therebetween, a source of fluid, a normally open valve port in one of said members establish` ing communication between said source of iiuid and said chamber, a valve member movable to close said port, an actuating member movable with respect to said valve men/iber,l means on said valve member frictionally Vengaging said actuating member. to couple said actuating member and said valve member for conjoint, movement, and means for moving said actuating member. to move-said valve member to close said port; said valve member and saidV actuating member dening a dashpot chamber therebetween, one of said last-named members having bores therein establishing communication .between said firstl namedv chamber and saidv dashpot chamber, the fluid in said d'ashpot chamber serving to assist in coupling said actuating member and said valve member for conjoint movement upon movement of said member.

8. A hydraulic valve lifter comprising a pair of relatively movable members denning a chamber therebetween, a source of fluid, a normally open valve port in one oi said members establishing communication between said source of fluid and said chamber, a valve member movable to close said port, means for moving said valve member to close said port, means for limiting movement of said valve member in the direction to open said port, and means establishing frictional driving engagement between said valve member and said means for moving same to accommodate relative movement therebetween after movement of said valve member is limited, whereby movement of said valve member is al- Ways uniform.

9. A hydraulic valve lifter mechanism for use in a valve drive train for a valve of an engine, the engine having a pressure lubrication system, comprising a pair of body members movable with respect to each other to maintain substantially zero clearance in the valve drive train, said body members defining a chamber therebetween, a normally open port in oneof said members establishing communication between the engine lubrication system and said chamber whereby said chamber is constantly iilled with lubricating fluid, a valve member movable to close said port whereby said chamber is closed to prevent relative movement between said body members in one direction, an actuating member movable with respect to said valve member, said actuating member being formed integrally with the other of said body members, and means for coupling said actuating member and said valve member for conjoint movement, the engine including means for moving said other body member and said actuating member to move said valve member to close said port.

10. A hydraulic valve lifter mechanism for use in a valve drive train for a valve of an engine, the engine having a pressure lubrication system, comprising a pair of body members movable with respect to each other to maintain substantially zero clearance in the valve drive train, said body members defining a chamber therebetween, a

normally open port in one of said members for establishing communication between the engine lubrication system and said chamber whereby said chamber is constantly iilled with lubricating fluid, a valve member movable to close said port whereby said chamber is closed to prevent relative movement between said body members in one direction, an actuating member movable with respect to said valve member, said actuating member being slidably mounted in the other of said body members and extending to the exterior thereof for actuation independently of said body members, and means for coupling said actuating member and said valve member for conjoint movement, the engine including means for moving said actuating member to move said valve member to close said port.

1l. A hydraulic valve lifter mechanism for use in a valve drive train for opening and closing the valve of an engine, the engine having a pressure *I lubrication system, comprising an outer body member having a bore therein, an inner body member mounted for sliding movement in the bore of said outer body member, said outer body member and said-inner body member defining a pressure chamber therebetween-said inner body member having a normally open portV therein for establishing communication between the engine lubrication system and said pressure chamber whereby said chamber is constantly iilled with lubricating fluid, the fluid in said pressure chamber acting to normally bias said body members away from each other and accommodating relative movement of said body members toward each other to maintain substantially zero clearance in the valve drive train in the closed position of the engine valve, a valve member movable to close said port in said inner body member whereby said pressure chamber is closed to prevent relative movement between said body members in one direction, cam means for operatively engaging said outer body member to effect movement of said body members, and mechanical means operatively disposed between said outer body member and said valve member for substantially positively moving said valve member to close said port in response to initial engagement substantially of said cam means with said outer body member whereby said inner body member is moved conjointly with said outer body member by said cam means.

l2. A hydraulic valve lifter mechanism for use in a valve drive train for opening and closing a valve of an engine, the valve drive train having fluid passageway means therein for connection with the pressure lubricating system of the engine, comprising an outer body member having a bore therein, an inner body member slidably received within the bore of said outer body member, said body members defining a pressure chamber therebetween, spring means between the inner end of said inner body member and the adjacent end of said outer body member normally biasing said inner body member away from said outer body member and accommodating movement of said body members toward each other to maintain substantially zero clearance in the valve drive train in the closed position of the valve, a cage held against the inner end of said inner body member by said spring means, a valve member positioned within said cage, second spring means biasing said valve member away from said inner body member, a limit stop defined by said cage and said valve member, a port in said inner body member establishing communication between said fluid passageway means in said valve drive train and said pressure chamber, said valve port providing a valve seat at the inner side of said inner body member in alignment with said valve member, said limit stop defining the separation between said valve member and said valve seat, said valve member being adapted to be moved into engagement with said valve seat to close said port whereby said pressure chamber is closed to prevent relative sliding movement between said inner body member and said outer body member, an actuating member slidable with respect to said valve member, means for coupling said valve member and said actuating member for conjoint movement, cam means for operatively engaging said outer body member to effect movement of said body members, said actuating member being moved by said cam means to move said valve member against said valve seat to close said port in said inner body member, whereby said pressure chamber is closed to lock said outer body member and said inner body member together for conjoint movement by said cam means to open the engine valve, said means for coupling said actuating member and said valve member 17 for conjoint movement being capable of accommodating relative movement between said actuating member and said Valve member.

13. A hydraulic valve lifter mechanism according to claim 12, in which the actuating member is formed integrally with said outer body member to eiect movement of said valve member during the initial movement of said outer body member by said cam means.

14. A hydraulic valve lifter mechanism according to claim 12, in which said actuating member is slidably mounted in said outer body member and extends to the exterior of said outer body member for independent actuation by said cam means prior to movement of said outer body member by said cam means.

15. A hydraulic valve lifter mechanism according to claim 12, including chamber means defined by said valve member and said actuating member, and iiuid passageway means in said valve member connecting said chamber means with said pressure chamber.

GLENN T. RANDOL.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,624,497 McAllister Apr. 12, 1927 2,010,157 ribbetts Aug. 6, 1935 2,014,659 Moorhouse Sept. 17, 1935 2,019,444 Church Oct. 29, 1935 2,146,550 Pierce Feb. 7, 1939 2,272,074 Voorhies Feb. 3, 1942 2,394,354 Barr Feb. 5, 1946 

